Electric switch



April 17, 1934. KNOWLEs r AL 1,955,132

ELECTRIC SWITCH Filed Dec. 19, 1931 2 Sheets-Sheet 1 w'wwaw April 1934- H. H. KNOWLES ET AL 1,955,132

ELECTRIC SWITCH Filed Dec. 19, 1931 2 Sheets-Sheet 2 INVENTO (7% W 0 WM l atented Apr.

PATENr oFFicE ELECTRIC SWITCH Harry H. Knowles, Birmingham, and George N.

Lemmon, Homewood, Ala.

Application December 1 9 Claims.

The purpose of our invention is to provide an automatic air break switch which opens farther than is usual, which opens and closes with minimum friction, and which is readily adaptable to 5 a wide variety of special uses.

Referring to the drawings, Fig. 1 shows in a small scale a general side elevation of one phase of the switch; Fig. 2 is a plan view of the blade and current-carrying parts; Fig. 3 is a view of some of 9 the same parts but with the blade partly opened; Figs. 4 and 5 are plan views of the operating arms; Fig. 6 is an enlarged side elevation of the triprelease mechanism; and Fig. 7 is an inverted plan view of the same device with the cover 39 and the conduit 40 removed. Figs. 8, 9, and 11 are details.

Upon a base 1 are mountedtwo stationary insulators 2, 3, a rotating insulator 4, and a tubular insulator 5. The insulator 2 carries the jaw mounting 6 in which are housed the contactors 7. These contactors are located in a movable support 8 which is pivoted about the post 9. Compression springs 10 keep the contactors normally pressed outwardly, thereby allowing some motion while maintaining a good contact. Flexible conductors 11 make direct connection with the stationary conductor 12. Stops 13, 14 limit the amount of motion of the support 8 about its 1 pivot 9.

Upon the rotatable insulator 4 is rigidly supported the tubular blade 15, which has a solid contact terminal 16 to engage; with the contactors I. A clamp 17 and a bolt 18 provide means to adjust the length of blade which extends from 4 towards 2. Arcing horns 19, 20 are arranged in the well-known way.

The usual pipe rods and cranks used for switch operation act best when their travel does not much exceed 90. Power applied to a crank is most efiective when the angle of application is nearest to 90. When the crank of a switch travels 90, power is applied to it at each end of the cranks travel at an angularity of only but it is sometimes desirable to open a high voltage switch 135 or even more, in order that the arc between the horns in each phase shall be drawn out as long as possible, without swinging together the arcs of adjacent phases.

In order to effect this we provide a bearing 21 which carries the arm 22 to which is attached the link 23 which is also connected to the arm 24, which is rigidly connected with the rotatable insulator 4. The arm 22 is also connected to the connecting rod 25 which is connected similarly to the two other phases of the complete switch.

9, 1931, Serial No. 582,048

Fig. 4 shows the closed position of the parts and Fig. 5 shows their position when the switch is open. It will be seen that the angular motion 26 of the arm 24 is approximately 150, although. power is never applied to the crank 24 at a less advantageous angle than about This is possible only by having the distance between 28 and 50 greater than the distance between 28 and the axis of the crank 24; so that the pivot 50 partially follows 51 around the arc of its travel. This principle can actually provide 180 of motion for the arm 24 without applying power from 23 at a sharper angle than 45.

The arm 22 is rigid with the shaft 28, which extends through the bearing 21, through the movable housing 30 and carries at its lower end the fixed crank 31 and the nut 29. The housing 30 carries the latch arm 32, which engages with the roller 33 and also the latch 34 which engages with the tip 35. A solenoid and its plunger 36 provides a means to release 34 and therefore 32 and 31. The housing 30 is free to turn about 28, and a crank 37 clamps about 30 in whatever position may be desired.

An auxiliary switch 38 is arranged to open the circuit of the solenoid 36 when the crank 31 is in the unlatched position, as shown by the dotted lines in Fig. 7.

A dished cover 39 protects all parts from damage and a conduit 40 passes through the cover in line with the shaft 28, and carries the insulated conductors 41, 41'.

From the insulator 4 a conductor 42 connects with the solenoid within the housing 43, which is. in series with the main line circuit. The plunger of this solenoid is attached to a long insulating rod which extends down'to the contact-making device within the housing 44. The circuit for this device is inside the conduit 45. A spark-gap 46. allows a lightning surge to by-pass the series solenoid without puncturing its insulation.

A suitable spring, as at 47, tends always to open the main switch unless it is positively held closed by a handle and a member attached togr the crank 37.

The device operates as follows,-current from the main conductor 48 passes through the blade 15, through the solenoid in the housing 43 and so to the line 49. Overload in the circuit lifts the plunger of the solenoid, closes the contact inside the housing 44. This completes a low voltage circuit through the solenoid 36, so the latches are released and the spring 47 opens the main line switch. This happens without any movement of the housing 30, as the shaft 28 and the crank 31 rotate inside of 30.

To operate the switch manually the handle which is connected with the crank 3'? is moved to 5 the open position. The latches thereupon engage with the crank 31 and the switch is entirely under manual control. At any time, however, that an overload passes through the solenoid in the main line, the switch swings to open position regardless of the manual control.

It should be noted that the crank 37 is close to the bearing 21 this makes for low stresses upon the bearing. Also this crank can, by the clamping bolts 37, be fixed to the housing in any position desired so that the operating handle can be located in the most convenient place, and proper angularity can be easily secured.

Leaving the lower side of the housing on hampered by operating parts, makes it possible to bring the conduit 40 and its wires into the housing at its axis so that the conduit can be stationary even though the housing moves. The conduit 40 is held loosely to the cover 39 as shown in'cross section in Fig. 11.

We claim:

1. In an electric switch, a relatively short driven crank and a relatively long curved driving crank rotatable about adjacent pivots, the driven crank being connected to the base of an insulator,

a'switch-arm supported by the insulator, the line ofcenters of the curved driving crank being rotatable to both sides of the plane connecting the axes of the pivots with the curved crank at one end of its travel, partially encompassing the insulator base and a link connecting the two cranks.

2. In an electric switch, a relatively short driven crank and a relatively long curved driving crank rotatable about adjacent pivots, the short crank being connected to the base of an insulator, the line of centers of the long curved crank being rotatable to both sides of the plane connecting the axes of the pivots with the curved crank at one end of its travel partially encompassing the base of the insulator, and a'link connecting the two cranks, together with a link connecting the long crank with a similar adjacent mechanism.

3. In an electric switch, a rotatable insulator, a clamp mounted upon the insulator, a rigid tubular switch arm held by the clamp, said arm being longitudinally adjustable in the clamp and having a transverse contact face across its free end, and a movable contact member mounted upon a second insulator and cooperable with the said transverse face.

4. In an electric switch, a rotatable support with an insulator thereon, a crank connected to the said insulator support, an operating crank pivoted near the insulator support, a connecting link between the insulator crank and the operating crank, the said link being connected to the operating crank at a greater distance from the operating crank pivot than the distance between the pivots of the two cranks.

5. In an electric switch, a relatively short driven crank and a relatively long curved driving crank rotatable about two adjacent pivots, the driven crank being connected with the base or" a movable insulator, the free end of the driving crank swinging in an are which is part of a circle which surrounds the pivot end of the driven crank, the curved crank being movable into a position which partially encompasses the base of the insulator, together with a link connecting the free ends of the cranks.

6. In an electric switch, a relatively short driven crank and a relatively long driving crank rotatable about adjacent axes, the driven crank being connected to the base of an insulator, a switch arm supported by the insulator, a link connecting the two cranks, and the line of centers of the driving crank being rotatable to both sides of the plane connecting the said axes.

7. In an electric switch, a relatively short driven crank and a relatively long driving crank rotatable about adjacent axes, the short crank being connected to the base of an insulator, the

line of centers of the long crank being rotata--' ble to both sides of the plane connecting the said axes, and a link connecting the two cranks, together with a link connecting the long crank with a similar adjacent mechanism.

8. In an electric switch, a rotatable support with an insulator thereon, a crank connected to the said insulator support, an operating crank pivoted near the insulator support, a connecting link between the two cranks, the said link being connected to the operating crank at a greater distance from the operating crank axis than the distance between the axes of the two cranks, and the line of centers of theoperating crank being operable to both sides of the plane connecting the axes of the two cranks.

9. In .an electric switch, a relatively short driven crank and a relatively long driving crank rotatable about two adjacent axes, the driven crank being connected with the base of a movable insulator, the line of centers of the driving it;

crank being operable in a segment of a circle which segment encompasses the axis of the driven crank, togetherwith a'link connecting the free ends of the cranks.

HARRY H. KNOWLES. GEORGE N. LEMMON. 

